A London investment fund is snapping up two major development sites in Northern Ireland.

The deal reportedly includes the Sirocco Quays site in east Belfast, and Castlebawn in Newtownards, Co Down. The identity of the London fund has not yet been revealed.

A billboard put up by real estate agency Colliers earlier this month has been updated to reflect the purchase of Sirocco.

At one stage, the quays were to be transformed in a £600m investment. But the sprawling industrial area has been sitting largely disused for years after the developer went under. The site was previously in the hands of vulture-fund Cerberus.

Plans for the waterside development included 5,000 apartments, a hotel, an international convention centre, a supermarket, leisure facilities and other retail sites.

Asda had been tipped as operator of the supermarket.

Ewart Properties sold the Sirocco site for £40m to the Carvill Group in 2006.

The proposal was once billed as “a new cultural destination for the city” and one of Carvill Group’s flagship Belfast projects.

Planning permission was granted for the ambitious development.

However, Carvill, which made its name in construction as well as housebuilding, went into administration in 2011.

It is understood Belfast City Council’s city and regeneration committee held a closed-doors meeting on the future of the Sirocco site last month. On the agenda was what could be done to revamp and rebuild the area once a new buyer was found.

In May, it was reported that Ulster Bank had sold Northern Ireland property loans originally worth £1.4bn for £205m in a deal with the US investment firm Cerberus. Loans originally taken out by Carvill Group on the Sirocco Works in east Belfast and by Leaside Investments for the proposed Royal Exchange shopping centre in the city were believed to be part of the massive deal. The Sirocco site was one of the highest-profile in Belfast affected by the loan sale.

The economic crash and collapse in property prices were seen as big factors in the demise of Warrenpoint-based Carvill Group and its plans for the site.

Meanwhile, the Castlebawn project in Newtownards, Co Down, is also said to be ‘sale agreed’ with the same London investment firm.

Back in 2012, the go-ahead was given for a £50m retail development at the site.

The 20,000 sq metre development was predicted to create 220 building jobs and 410 full and part-time employment positions. But the shopping centre part of the development, which had received planning permission, was quashed after a judicial review.

And in 2015 there was serious doubt cast over the site’s future after investment fund Cerberus appointed KPMG as administrators to the firm behind the development.